Preheat oven to 375°F (190°C). Grease a standard 12-cup muffin tin.

In a small saucepan, combine peaches, brown sugar, cornstarch, cinnamon, vanilla, and lemon juice. Cook over medium heat until thickened (about 5–7 minutes). Let cool.

Roll out each puff pastry sheet on a lightly floured surface. Spread peach filling evenly over each sheet.

Roll each sheet tightly into a log. Slice each log in half lengthwise to expose layers.

Twist each half into a spiral and place into a muffin cup, cut side facing up.

Brush tops with melted butter.

Bake for 25–30 minutes, or until golden and puffed.

Let cool slightly, then dust with powdered sugar if desired.